Since you're a newbie I can understand why you submitted a post with lack of information. Is the partition your mounting is truly an NTFS partition? Where are you clicking? (Within Filemanager)? If you can, can you post any relevant logs from /var/log/messages (are similar pertaining to your Distro)? Can you try to mount the filesystem manually from console, if you're familiar with a console? What DE are you using? Is the Partition residing USB Mass Storage Device?